This invention relates to an apparatus and a method for material handling, and more particularly relates to material handling in loading and unloading a railcar.
A commonly used approach for loading and unloading railcars has involved the use of a mobile apparatus which is perched upon the top of a railcar so as to derive all support from the railcar during material handling operations and even during movement of the apparatus from one railcar to another. This approach has the disadvantage of imposing all of the weight of the apparatus upon the upper surface of the walls of a gondola railcar, a burden for which the walls are not designed. Also, because this approach relies upon the railcar for total support, there is no independent stabilization support of the railcar for the purpose of restricting lateral wobble movement and longitudinal roll movement of the railcar during the rigors of loading and unloading. Apparatus perched atop a railcar in fact contributes to lateral wobble movement because of the high center of gravity.
An alternative approach for loading and unloading railcars has been that of using mobile free-standing apparatus. When free-standing apparatus is used, the contact between the railcar and the apparatus is minimal or non-existent Lateral wobble movement and longitudinal roll movement of the railcar are unrestrained by this type of apparatus just as they are unrestrained by apparatus perched atop a railcar.
Insofar as known, no one has heretofore successfully provided highly mobile railcar loading and unloading apparatus of versatile character having features which permit an operator to effect selected pressures on a railcar so as to reduce or eliminate lateral wobble movement and also longitudinal roll movement during loading and unloading operations, plus features which allow an operator to take advantage of a selected degree of railcar support for boom operations of loading and unloading, and also features which at the same time save undue weight impact on parts of the railcar not originally designed to withstand the full weight of loading and unloading apparatus. It is to a solution of this problem that this invention is directed.